Sectional digital selector switch construction

ABSTRACT

The invention provides a composite multiple selector switch, and switch units therefor, for displaying in-line indications of information signals that may be selected by independent manual adjustment of the individual switch units. Each switch unit comprises a stationary switch structure having stationary contacts and a rotary switch structure having rotary contacts which are selectively brought into registry to display a symbol corresponding to the selected information signal. Each of the rotary structures includes a wheel having a plurality of lugs, at least one of which projects at any one time radially outwardly and is accessible through an open window of a switch panel on which the composite switch unit is mounted.

waited tates Patent I 72] Inventor Harry Dudley Wright Pasadena, Calif.

[21] Appl. No. 866,426

[22] Filed Oct. 6, 1969 [45] Patented Feb. 23, 1971 [73] Assignee Becton Dickinson Electronics Company Pasadena, Calif.

Continuation of application Ser. No. 265,315, Mar. 12, 1963, which is a division of application Ser. No. 820,543, J une 5, 1959, Patent No. 3,089,923.

{54] SECTIONAL DIGITAL SELECTOR SWITCH [56] References Cited UNITED STATES PATENTS 1,555,969 10/1925 Hatch 200/167 1,564,551 12/1925 Gates 200/63 1,656,227 l/1928 Patchin 40/68 2,414,191 l/1947 Coon 200/6 2,421,881 6/1947 Heasty.. 200/155 2,632,058 3/1953 Gray 179/15 2,662,949 12/1953 Christensen et al. 337/45 2,799,740 7/1957 Blackman 200/14 2,804,706 9/1957 Sandri 40/68 2,824,191 2/1958 Christensen.. 337/50 2,827,626 3/1958 DeMOtte 340/347 I 2,845,226 7/1958 Cummings et al... 235/117 2,853,564 9/1958 Gahagan 200/11 2,861,130 11/1958 Yanagida 179/90 2,874,338 2/1959 Pease 317/99 2,967,917 l/l96l Cole 200/50 3,089,923 5/1963 Wright 200/5 FOREIGN PATENTS 247,880 l/1948 Switzerland. 264,371 9/1913 Germany. 282,955 3/1915 Germany. 323,440 9/1957 Switzerland. 420,222 11/1934 Great Britain. 577,897 6/1946 Great Britain. 665,854 10/1938 Germany. 760,989 12/1933 France.

1,003,837 1/1959 Germany.

OTHER REFERENCES BULLETINS 6631-589D and 6635-594d by Messrs. Contraves,journal Regelungstechnik, 1957, Vol 1 1, p. 418 and Vol. l2,p. 459,journal Control Engineering, July 1958, p. 94.

Susskind: Notes on Analog Digital Conversion Techniques, p. 6-40 to 6-44, MIT Wiley & Sons Inc., New York, 1957.

Steinbuch, K.; Taschenbuch der Nachrichtenverarbeitung, Berlin-Gottingen 1962, p. 76 et seqq. 777, 778; prospectus by Messrs. Ebe, p. 1 1.

Primary Examiner-Robert S. Macon Assistant Examiner.I. R. Scott Att0rney-Reed C. Lawlor ABSTRACT: The invention provides a composite multiple selector switch, and switch units therefor, for displaying inline indications of information signals that may be selected by independent manual adjustment of the individual switch units. Each switch unit comprises a stationary switch structure having stationary contacts and a rotary switch structure having rotary contacts which are selectively brought into registry to display a symbol corresponding to the selected information signal. Each of the rotary structures includes a wheel having a plurality of lugs, at least one of which projects at any one time radially outwardly and is accessible through an open window of a switch panel on which the composite switch unit is mounted.

SECTIONAL DIGITAL SELECTOR SWITCH CGNSTRUC'IKON This is a continuation of application Ser. No. 265,315 filed Mar. 12, 1963, which is a divisional application of application Ser. No. 820,543, filed Jun. 5, 1959, now US. Pat. No. 3,089,923,May 14, 1963.

An important object of this invention is to provide a novel digital switching unit, by means of which a plurality of substantially identical such units may be arranged in a compact in-line series to provide for counting to as high a number as may be desired.

Another object of the invention is to provide an emcient digital switching unit, especially one containing electrical switching means, which is easilyduplicated for assembling into a multiple in-line switching system to whatever extend needed for any given purpose.

A still further object of the invention is to provide a digital switching unit embodying a finger-operated wheel positioned to be engaged by an operators finger for positive movement of the wheel, one step at a time or two steps at a time, to advance the wheel for bringing into viewing position digits delineated thereon, such digits being successively advanced by the operator. A

A still further object is to provide the wheel of such a switching unit with notches which are employed to advance the wheel from one position to. another and which also cooperate with a spring to set and retain the wheel in a predetermined position.

A still further object of the invention is to provide means in such a switching unit for positively limiting movement of the operator's finger to one digit spacing at a single operation.

A still further object of the invention is to provide means in such a switching unit for readily setting the wheel in a predetermined position as the operator's finger is withdrawn after operating the switching unit.

An additional object of the invention is to provide, in conjunction with a rotary switching wheel in each unit, an electrical switching device for completing electrical circuits as the respective wheels are rotated digit by digit, whereby to conduct electrical currents through such completed circuits to an instrument into which they are to be fed.

It is a still further object to provide a switching unit of the indicated character having a casing providing means for rotatably mounting a switching wheel in the casing, the casings being so arranged that a series of such casings are alignable to mount their respective switching wheels and also the appropriate sides of the adjacent switching wheels in an aligned assembly.

Other objects of the invention, and various features of construction thereof, will be apparent to those skilled in this art, upon reference to the following specification and the accompanying drawings wherein certain embodiments are disclosed to indicate what is presently deemed to be the best manner of constructing and employing the invention.

In these drawings:

FIG. 1 is a face view of a multipleswitching system of this invention made up of three aligned switching units and two end plates assembled therewith; 7

FIG. 2 is a cross section taken from the line 2-2 of FIG. 1 on an enlarged scale;

FIG. 3 is a similar cross section taken from the line 3-3 of FIG. 1;

FIG. 4 is a transverse cross section taken from the line 4-4 of FIG. 2;

FiG. 5 is a detail showing of a wiper switch;

FIG. 6 is a view similar to that of FIG. 2, but showing switching mechanism employing a binary system as distinguished from the decimal system of FIGS. 2 to 5;

FIG. 7 is a cross section corresponding with that of FIG. '3, but illustrating the binary system switching mechanism of FIG. 6; and

FIG. 3 is a detail of the wiper switch of FIGS. 6 and 7.

As indicated in FIG. 1, three casing units, or casings 10, which are substantially identical in construction, are shown as being assembled to form a composite stationary switch unit for the purpose of performing in-line counting operations up to 999. At each end of the assembly of the three casing units it), there is provided an aligned end plate 12 retained in assembled position by the same means which retain the casing units 10 in assembled position, as more fully described hereinafter.

The casing, or switch compartment 10 in each unit, as the assembly of FIG. 1 is viewed in elevation, includes a top wall 14 (FIGS. 2 and 3) which is relatively narrow as compared with its length, a front wall in the form of two spaced wall sections 16, and a bottom wall 16, these having the same narrow configuration as the top wall 14. In addition, each casing unit 10 has a back wall 18 as seen in FIG. 2, which is somewhat narrower than the walls l4, l5, and 16, to provide a narrow slotlike space for the reception between the walls 14 and 16 of a projecting rearward end of a circuit board 20, as presently to be more fully described. Additionally, each casing unit 10 is provided at one side with a sidewall 22. All of the described wall portions may be integral with one another, as conveniently provided by a molded thermosetting plastic construction. As seen at the right of FIG. 2, the end of the circuit board 20 projecting beyond the back wall 18 is that of the circuit board of the unit 10 lying immediately behind the walls 18 and 22 shown in elevation. In the invention shown, the circuit board, or stationary switching member, 20 acts as a sidewall. Each end plate i2 is desirably stamped from sheet metal to provide a side closure plate 23 and an integral right-angularly disposed flange 24, as presently more fully described.

The spaced portions 15 of the forward wall of each casing 10 provide a generally rectangular open window 25 between them, which window is the width of the wall sections 15 and the upper and lower walls 14 and 16. In addition, the upper edge of the sidewall 22 is provided with a laterally outwardly directed and somewhat elongated lip 26, which overhangs the circuit board 20 of the adjacent casing unit and which, as seen in FIG. 1, is at the left of its window 25. Additionally, each elongated lip 26 is provided at its opposite ends with short inwardly overhanging flanges or lips 27, the elongated lip 26 and the short lips 27 cooperating among them to define an inner window 28 for viewing a digit presented on a switching, or operating, wheel 30. The casing 10 and circuit board 20 of each switch unit forms a stationary switch structure. The operating wheel 30, including its hub 32 and cylindrical rim 36, together with the finger lugs thereon and also the electrical contacts thereon, constitute a rotary switch structure.

Each switching wheel 30 includes a body portion or hub section 32 from which extends outwardly a radially directed circumferential finger flange 33, which is arcuately notched at 34 to provide curved finger lugs 35 for rotating the wheel. The

finger flange 35 lies at one side of its wheel 30, and at the op posite side of wheel 30 there is provided a cylindrical rim 36, which carries a series of 10 digits, 0 to 9 of the decimal system, as indicated in FIG. 1, these digits lying'alongside the finger lugs 35, of which there are also 10 in number. This rim 36 rotates beneath the small inwardly overhanging flanges 27 so that, as each digit is moved into position, it is viewed through the small window 28 provided between the small overhanging flanges 27 and between the elongated outwardly overhanging flanges 26 and the finger flange 33 and its lugs 35; the finger flange 33 thus extends outwardly alongside the overhanging window-forming flanges 27 and rotates adjacent the side edges thereof.

The hub or body portion 32 of each switching wheel 30 is centrally provided at its opposite sides with pivots 38, which may be integral with the wheel 30, especially where the entire wheel is cast or is molded from thermosetting plastic or the like. These pivots 38 may be journaled in bores providing bearings, such as a bore in an adjacent boss 40 in each sidewall 22 and a bore in an appropriate bearing 41 provided in each circuit board 20, as best illustrated in FIG. 4.

Each circuit board is secured in place by means of screws 42, which are threaded into appropriate cast bosses at the corners of the respective casing units 10. Additionally, the circuit boards 20 may be bound in place by meansof through bolts 44 which extend entirely through the assemblage of the several casing units it) and the end plates 12 seen in FIGS. 1 and 4, these bolts 44 being positioned in bores in appropriate corner bosses of the casing units as illustrated in FIGS. 2, 3, and 4.

By the indicated mounting of the various switching wheels 30, the latter may be readily rotated to advance the various digits into the viewing positions indicated in FIG. 1, the operators finger being disposed in a notch 34 and drawn forward against a finger lug 35 until his finger engages the nearer front wall portion or section 15, whereupon the rotary movement of the wheel 32 ceases. These wall sections 15 thus act as finger stops or finger guides.

In cross section, the notches 34 form arcs of about 100 to 140. Each notch is shaped to receive the distal portion of an operators finger. The surfaces 15a of the front walls slope in directions that extend along the ends. of the notch arcs at both ends of the window 25, being about tangential to the ends of the arcs. With this arrangement, as the operators finger moves the wheel from one position to another, the notches and the digit to be viewed are registered accurately in the window as the finger is withdrawn, and then the wheel is held by virtue of the friction produced by the force between the switch contacts.

For the purpose of' securely centering of a finger lug 35 in the position to which the corresponding wheel 30 has been rotated, a centering spring 45 is provided within and at the back of each casing unit 10. One end of the spring is shaped to fit into slots provided between a boss '46 that receives one of the screws 42 and the adjacent bottom wall 16 and part of the spring engages the adjacent rear wall 18 of the corresponding casing unit 10 in order to anchor the spring in place. Such slots are indicated at 48 in FIG. 2, which also shows an offset reten tion finger 45a at the fixed extremity of the spring 45 to insure proper spring position. The other end of the'spring 45 is movable and is shaped to match the curvature of the finger notches 34. Thus, when a switching wheel 30 has been rotated by the operator's finger to bring a digit into'viewing position in the center of the small viewing window '28, and the operator's finger has engaged against a finger stop wall section 15, as indicated in FIG. 2, the curved free extremity of the spring 45 settles down into a corresponding finger notch 34 and retains the respective wheel 30 in the new position. For some uses, the spring 45 might be omitted. In such case, friction between various members is relied upon to retain the switching wheel in place. However, the use of the spring 45 is better, since it provides a more positive holding action, especially when the unit is subjected to vibration or shock forces. In prior devices, stiff springs have been used for registering rotatable wheels in desired positions. But, since registration is accomplished in this invention as a result of the shapes of the window edges in relation to the shapes of the notches, a soft spring may be em- I ployed, since their sole function is to retain the wheel in position, not to force it into position.

It will be noted, also, that the notches 34 and finger lugs 35 of the wheels 30 ,are adapted to rotation of the wheels two steps at a time, as by two increments of motion through the action of the thumb. As indicated in phantom in FIG. 6, the ball of the thumb first operates against one lug 35 to move a wheel 30 one step forward and the distal end of the thumb then operates against the next lug 35 to move the wheel a second step forward. Further, in view of the symmetrical construction of the lugs 35 of each wheel 30, the wheels may be rotated in the opposite direction if desired for any reason, the end of the operators finger pushing against the exposed lugs 35.

In connection with the assembling of a. plurality of easing units 10 and end plates 12 into a complete assemblage such as shown in FIG. 1, the lip 26, which overhangs the outside of each casing unit ii) (to the left as viewed in FIG. 1) and which is integrally positioned at the top of the corresponding sidewall 22, is arranged so as to interlock at its ends under the inclined or beveled edges of the two finger-stop wall portions 15 shown in FIGS. 2 and 3. For this purpose, the length of the overhanging flange 27 in each instance is slightly greater than the length of the window opening 25 between the finger-stop wall portions 15; this is best indicated at the left of FIG. 1. Thus, when one unit 10 is being assembled alongside an adjacent unit, such extending lip portions, indicated at 52 in FIG. I, lock under the beveled edges 50 of the adjacent stop portions 15. Such arrangement also helps'maintain the interior of the assembly dust free. 1

For the purpose of accommodating an overhanging lip 26 in an end plate 12 as seen at the left of FIG-1, the latter is correspondingly slotted at 54 to receive the lip 26. Such a slot 54 is also seen at the right of FIG. 1 in the other end plate 12. Each slot 54 exposes the corresponding upper edge portion of the main plate or sidewall 23 of the respective end plate 12. In order to cover the slot 54 of the end plate 12 seen at the right of FIG. 1, and also to conceal the upper edge of the corresponding circuit board 20 and the adjacent sidewall 23 when the assembly is completed, the flange 24 of this right end plate 12 is desirably covered with a thin, stiff finish layer 55, which may be of heavy metal foil, and which is shown as approximately half broken away. This layer 55 is provided with an overhanging extension tongue 55a corresponding in size with the lips 26 of the casing units 10 to partially enter the larger window 25 and overhang the adjacent circuit board 20. In addition to serving as a closure plate or finish layer, the member 55 may at the same time be a name plate. It is secured in position as by means of screws 56 received in screw holes 58 in the end plate flange 24, and said screws 56 are desirably employed to mount the assembly on a switch panel in the customer's apparatus for which this switching mechanism has been developed. Such switch panel customarily has an open window in which the assembly is mounted so that the lugs 35 and the digits are visible and accessible through the open window of the panel.

The function of switching wheels 30 is to make and break circuits corresponding with the digits on the respective cylindrical rims 36, and this is accomplished through the medium of the mentioned circuit boards 20 and rotary contact means, such as rotary wiper switches 60 concentrically mounted about the axes of the switching wheels 30 in position to make 'and break circuits by means of contact members on respective circuit boards 20.

Each circuit board 20' receives and centers one of the pivot shafts 38, and the board carries so-called printed circuits having stationary contact means which include the contacts or switch means to be engaged by the rotary wiper switches 60. Adjacent the respective axis or pivot shaft 38, each board 20 carries a printed continuous wiper ring or slip ring 62, and concentric therewith outside the wiper ring or slip ring 62, there is provided a circular series of printed contact segments 64 spaced from each other and constituting a commutator ring and corresponding with the 10 digits on the rim 36 of the respective switching wheel 30. Printed leads 65 extend from the various contacts or ring segments 64 to appropriate terminals 66 at the projecting end of the respective circuit board 20 where they may be wired into any instrument with which the present digital switch is to be used. Some of the leads 65 are disposed on one side of the board 20, which is formed of insulating material, and some of them are provided on the other side, appropriate through-connections, such as indicated at 67, extending through the board from some of the contact segments 64 and the respective lead 65 on the other side.

As shown in FIGS. 2, 3 and 4, the decimal system is employed, and make-and-break fingers, or rotating contacts of each wiper switch 60 are positioned to contact successively the commutator segments or contacts 64 on the circuit board 20 as respective switching wheel 30 is rotated. Each wiper switch 60 has a central ring member 70 (FIG. 5) secured in any suitable manner as at 700 to the hub of respective switching wheel 39, and this ring member is in general positioned inside the locus of the slip ring 62, as well as inside the locus of the outer series of commutator segments or contacts 64. To the inner ring of each wiper switch 60, there are connected two wiper fingers 72 having contacting wiper terminals 74 (FIGS. 2 and 5) to engage the slip ring 62. Also connected to the inner ring of each wiper switch so is a pair of wiper fingers 75 having wiper terminals 76 disposed at the locus of the circular series of contacts 64 on the circuit board 20. These wiper terminals 76 may be spaced either to constitute the nonshorting break-before-make type of switching mechanism, or they may be more widely spaced to provide the shorting or make-before-break type of switching mechanism, according to the requirements of the circuits being switched.

With the mechanism thus described, as any one of the switching wheels 30 is rotated step-by-step to present digits thereon successively to the respective windows 28, circuits are completed through the respective circuit boards, contacts thereon and the wiping fingers 72 and 75 of the respective wiper switch 60. The corresponding impulses are then transferred from the terminal 66 to the customers instruments with which the present improvement has been connected by appropriate wiring.

,The electrical arrangement illustrated in FIGS. 2, 3, 4, and 5, as has been previously indicated,-is for use with a decimal electrical system. The present structure, however, lends itself readily to the employment of contact boards 20 and wiper switches 80 for use with binary electrical systems, and such an arrangement is illustrated in FIGS. 6, 7, ands, where the same casing units 10 and switching wheels 30,- with finger lugs 35, are employed as with the decimal arrangements of FIGS. 1 to 5 Instead of employing the decimal contact arrangement represented in the structure of FIGS. 1 to 5, a binary contact arrangement may also be employed, such as that represented in FIGS. 6, 7, and 8. In the switch illustrated in those FlGS., a decimal or scale-of-IO switching wheel 30 is employed, but the circular series of i stationary contact segments 64 of the contact arrangement of FIGS. 1 to Sis replaced by a plurality of concentric annular zones in order to provide a switching arrangement operating on a binary or scale-of-two basis. Also in this case, a five-fingered wiper switch 80 is employed in place of the wiper switch 60.

The wiper switch 80 includes four contact fingers 105, 106, 107, and 108, which are radially aligned, as well as an additional contact finger 102. The area of the contact board 20 through which the various contacts of the wiper switch 80 move is divided into 10 36 consecutive sectors 5,, 8,, 8,. Both the numbers of the digits indicated by any switching wheel and the numbers of the sectors, increase in a counterclockwise direction about the shaft 38. In this arrangement, five zonal contacts, or arcuate switch means, are employed. The inner contact 82 constitutes a slip ring which is engaged by the contact 102. The outer contact 84 is provided with five uniformly spaced inwardlyprojecting extension segments 85 that lie in sectors 8,, S S S and S A short zonal segment 86 extends over sectors S and S at the radius of the contact finger 106. A longer zonal segment 87 occupies sectors 8;, 8,, S and S at the radius of the wiper finger 107. And two spaced electrically connected segments 88 and 88a occupy sectors 8;, S S and S at the radius of the contact finger 108. With this arrangement, a coded binary output may be provided.

As illustrated in FIG. 7, the outer contact 84, together with its segments 85, are connected by a suitable printed circuit lead to terminal 94. Likewise, the contact 86 is connected by a suitable printed circuit lead to terminal 96. Similarly, the contact 87 is connected by a suitable printed circuit lead to terminal 97. And similarly, the two contact segments 88 and 880 are connected by a common printed circuit lead to each other and to a terminal 98. And the slip ring 82 is connected by a suitable printed circuit lead to terminal 92. The five terminals 92, 94, 95, 97, and 98 are arranged at the rear edge of the contact board 20 at the rear of the casing unit 10 to facilitate insertion of the unit into and removal from a suitable electrical contact plug.

With the above described arrangement of the segment 84 and its segments 85, 86, 87, 88, and 88a operating in conjunction with the wiper switch and its various contact fingers 102, 105, 106, 107, and 108, an appropriate binary code is readily followed and the present digital switching system readily employed in conjunction with apparatus designed for use with such coded arrangement.

From these disclosures, it is apparent that the digital switching system of this invention is readily applicable for employment with any appropriate numbers system, whether the system be decimal, binary, octal, or other usable number system. In any event, the operating wheels are movable by the operator between a number of discrete positions that correspond to various information signals that are generated and the wheels bear symbols corresponding to the different information signals.

Although only two specific embodiments of the invention have been illustrated and described, it will be obvious that the invention is not limited thereto, but is capable of being embodied in many other forms. Various changes which will suggest themselves to those skilled in the art may be made in the material, form, details of construction and arrangement of the elements without departing from the scope of the invention.

I claim:

1. In a multiple selector switch:

a plurality of switch units each of which comprises a stationary switch structure and a rotary switch structure;

the stationary switch structures being rigidly mounted together in a side-by-side relation along a rotary axis thereby forming a composite stationary switch unit, each switch unit being separate from the others;

each of said stationary switch structures having a switch contact board mounted transversely of said axis, each board having a plurality of stationary switch contacts mounted thereon;

means for mounting said composite stationary switch unit on a switch panel having an open-window section for receiving said composite stationary switch unit;

each rotary switch structure having an operating wheel mounted for independent rotary movement about said axis parallel to said panel;

each said wheel having on its periphery a plurality of lugs, successive ones of which are spaced apart by an amount sufficient to receive the distal portion of an operator's finger, at least one lug of each wheel projecting at any one time radially outwardly from said composite stationary switch unit and accessible through'such panel when said composite stationary switch unit is mounted thereon whereby said one lug is accessible from the front of said panel for operation by a finger of the user, a plurality of said lugs being located in a position .behind such panel at all such times;

each wheel being movable between a number of discrete positions corresponding to various information signals to be generated;

each wheel also bearing different symbols corresponding respectively to different information signals, a selected one of said symbols being registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions to generate the information signal corresponding to the selected one symbol; and each wheel carrying rotary contact means, said rotary con tact means of said switch unit cooperating with the stationary contact means of each switch unit for generating infonnation signal corresponding to each of said different symbols respectively when said each wheel is set to expose to view the corresponding symbol through said panel, the said discrete positions of the wheel being separated by regular angular spacings.

2. A multiple selector switch as defined'in claim 1 in which each wheel is angularly movable about said axis without limit in either direction.

3. in a multiple selector switch:

a plurality of switch units each of which comprises a separate switch compartment having a pair of sidewalls, a rear wall joining said sidewalls, top and bottom walls joining said sidewalls, and a front wall structure having an open window, each switch unit comprising a plurality of electric terminals extending outwardly of said compartment, a separate stationary switching member mounted in each compartment, each switching member comprising a plurality of stationary contact means connected respectively to said terminals, means for'mounting said units as a common compact rigid assembly with said units in side by-side relation with adjacent sidewalls of each pair of consecutive switch units in the assembly in adjacent sideby-side relation and with all saidfront walls on the same side of the assembly, means for mounting said assembly on a switch panel having an open panel window section exposing the windows of the respective switch units to view;

each switch unit also having anop'erating wheel mounted for independent rotary movement within a corresponding compartment about an axis parallel to the front of said corresponding compartment, each said wheel having on its periphery a plurality of lugs, successive ones of which are spaced apart by an amount-sufficient to receive the distal portion of an operators f nger,i at least one ing of each wheel projecting at any one time radially outwardly from said assembly and accessible through such panel when said assembly is mounted thereon whereby said one lug is accessible from the front of said panel for operation by a finger of the user, each wheel being movable between a number of discrete positions corresponding to various information signals to be generated, each wheel also bearing corresponding symbols, a selected one of which is registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions corresponding to the selected one indicia, each wheel carrying rotary contact means, said rotary contact means of each switch unit cooperating with the stationary contact means of each switch unit for generating a differentinformation signal corresponding to each of said different symbols respectively when said each wheel is set to expose to view the corresponding symbol throughsaid panel, the said discrete positions of the wheel being separated by regular angular spacings.

4. A switch as defined in claim 3 wherein each said compartment is substantially closed except for said open window in the front wall structure.

5. A multiple position selector switch unit comprising:

a switch compartment having a pair of sidewalls, a rear wall joining said sidewalls, top and bottom walls joining said sidewalls, and a front wall structure having an open window;

a plurality of electric terminals extending outwardly of said compartment at a position spaced rearwardly'from the front wall structure;

a stationary switching member mounted in said compartnient, said stationary switching member comprising a plurality of stationary contact means having contact surfaces that face axially, various contacts means being connected to different terminals;

means for mounting said switch unit on a switch panel having an open panel window section exposing the open window of said switch unit to view; and

said switch unit also having an operating wheel mounted for rotary movement within said compartment about an axis transverse to said sidewalls, said "wheel having on its periphery a plurality of finger lugs, successive ones of which are spaced a an by an amount sufficient to receive the distal portion 0 an operator's finger, at least one lug of each wheel projecting at any one time radially outwardly and accessible through said open window whereby said one lug is accessible from the front of said panel for operation by a finger of the user, said wheel being movable between 'a number of discrete positions corresponding to various information signals to be generated, said wheel also bearing corresponding symbols, a selected one of V which is registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions corresponding to the selected one indicia, said wheel'carrying rotary contact means on the side thereof, said rotary contact means cooperating with the stationary contact means of said switch unit for generating a different information signal corresponding to each of said different symbols respectively when said wheel is set to expose to view the corresponding'symbol through said panel, the discrete positions of the wheel being separated by regular angular spacings.

6. A selector switch as defined in claim 5 wherein said stationary contacts are connected to various combinations of terminals, each combination being associated with one digit of a digital system, the contacts being so connected that the figure to-which the switch is set in its digital system represents the same number as the combination of terminals thereby brought into circuit represent in their digital system, in which adjacent positions of the switch are separated by regular angular spacings and the switch is angularly movable without limit in either direction so as to be movable fromthe maximum figure to the minimum figure in the direction of increasing figures and vice versa. j-

7. A switch as claimed in claim 6 in which the digital system of the switch positions is a decimal system and the wheel is movable to any one of ten positions angularly spaced apart by approximately 36.

8. A multiple selector switch as defined in claim 5 wherein:

the stationary contact means on said stationary switching member comprising a plurality of radially-spaced apart arcuate switch means, and the rotary contact means on said wheel comprises a plurality of rotary contacts similarly spaced apart radially for contacting said arcuate switch means in various combinations as said wheel is rotated;

said rotary contacts being electrically connected together and to a common terminal throughout the wheel rotation; and

the rotary contacts being arranged to connect said common terminal to a different combination of four terminals in each of its positions to represent a unit's digit, a two's digit, a fours digit and an eight's digit in accordance with the binary system.

9. A switch as defined in claim 8 wherein each said compartment is substantially closed except for said open window in the front wall structure. I 

1. In a multiple selector switch: a plurality of switch units each of which comprises a stationary switch structure and a rotary switch structure; the stationary switch structures being rigidly mounted together in a side-by-side relation along a rotary axis thereby forming a composite stationary switch unit, each switch unit being separate from the others; each of said stationary switch structures having a switch contact board mounted transversely of said axis, each board having a plurality of stationary switch contacts mounted thereon; means for mounting said composite stationary switch unit on a switch panel having an open window section for receiving said composite stationary switch unit; each rotary switch structure having an operating wheel mounted for independent rotary movement about said axis parallel to said panel; each said wheel having on its periphery a plurality of lugs, successive ones of which are spaced apart by an amount sufficient to receive the distal portion of an operator''s finger, at least one lug of each wheel projecting at any one time radially outwardly from said composite stationary switch unit and accessible through such panel when said composite stationary switch unit is mounted thereon whereby said one lug is accessible from the front of said panel for operation by a finger of the user, a plurality of said lugs being located in a position behind such panel at all such times; each wheel being movable between a number of discrete positions corresponding to various information signals to be generated; each wheel also bearing different symbols corresponding respectively to different information signals, a selected one of said symbols being registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions to generate the information signal corresponding to the selected one symbol; and each wheel carrying rotary contact means, said rotary contact means of said switch unit cooperating with the stationary contact means of each switch unit for generating information signal corresponding to each of said different symbols respectively when said each wheel is set to expose to view the corresponding symbol through said panel, the said discrete positions of the wheel being separated by regular angular spacings.
 2. A multiple selector Switch as defined in claim 1 in which each wheel is angularly movable about said axis without limit in either direction.
 3. In a multiple selector switch: a plurality of switch units each of which comprises a separate switch compartment having a pair of sidewalls, a rear wall joining said sidewalls, top and bottom walls joining said sidewalls, and a front wall structure having an open window, each switch unit comprising a plurality of electric terminals extending outwardly of said compartment, a separate stationary switching member mounted in each compartment, each switching member comprising a plurality of stationary contact means connected respectively to said terminals, means for mounting said units as a common compact rigid assembly with said units in side-by-side relation with adjacent sidewalls of each pair of consecutive switch units in the assembly in adjacent side-by-side relation and with all said front walls on the same side of the assembly, means for mounting said assembly on a switch panel having an open panel window section exposing the windows of the respective switch units to view; each switch unit also having an operating wheel mounted for independent rotary movement within a corresponding compartment about an axis parallel to the front of said corresponding compartment, each said wheel having on its periphery a plurality of lugs, successive ones of which are spaced apart by an amount sufficient to receive the distal portion of an operator''s finger, at least one lug of each wheel projecting at any one time radially outwardly from said assembly and accessible through such panel when said assembly is mounted thereon whereby said one lug is accessible from the front of said panel for operation by a finger of the user, each wheel being movable between a number of discrete positions corresponding to various information signals to be generated, each wheel also bearing corresponding symbols, a selected one of which is registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions corresponding to the selected one indicia, each wheel carrying rotary contact means, said rotary contact means of each switch unit cooperating with the stationary contact means of each switch unit for generating a different information signal corresponding to each of said different symbols respectively when said each wheel is set to expose to view the corresponding symbol through said panel, the said discrete positions of the wheel being separated by regular angular spacings.
 4. A switch as defined in claim 3 wherein each said compartment is substantially closed except for said open window in the front wall structure.
 5. A multiple position selector switch unit comprising: a switch compartment having a pair of sidewalls, a rear wall joining said sidewalls, top and bottom walls joining said sidewalls, and a front wall structure having an open window; a plurality of electric terminals extending outwardly of said compartment at a position spaced rearwardly from the front wall structure; a stationary switching member mounted in said compartment, said stationary switching member comprising a plurality of stationary contact means having contact surfaces that face axially, various contacts means being connected to different terminals; means for mounting said switch unit on a switch panel having an open panel window section exposing the open window of said switch unit to view; and said switch unit also having an operating wheel mounted for rotary movement within said compartment about an axis transverse to said sidewalls, said wheel having on its periphery a plurality of finger lugs, successive ones of which are spaced apart by an amount sufficient to receive the distal portion of an operator''s finger, at least one lug of each wheel projecting at any one time radially outwardly and accessible through said open window whereby said one lug is accessible from the front Of said panel for operation by a finger of the user, said wheel being movable between a number of discrete positions corresponding to various information signals to be generated, said wheel also bearing corresponding symbols, a selected one of which is registered in an indicia indicating position where it is visible through the panel when the wheel is moved to one of said discrete positions corresponding to the selected one indicia, said wheel carrying rotary contact means on the side thereof, said rotary contact means cooperating with the stationary contact means of said switch unit for generating a different information signal corresponding to each of said different symbols respectively when said wheel is set to expose to view the corresponding symbol through said panel, the discrete positions of the wheel being separated by regular angular spacings.
 6. A selector switch as defined in claim 5 wherein said stationary contacts are connected to various combinations of terminals, each combination being associated with one digit of a digital system, the contacts being so connected that the figure to which the switch is set in its digital system represents the same number as the combination of terminals thereby brought into circuit represent in their digital system, in which adjacent positions of the switch are separated by regular angular spacings and the switch is angularly movable without limit in either direction so as to be movable from the maximum figure to the minimum figure in the direction of increasing figures and vice versa.
 7. A switch as claimed in claim 6 in which the digital system of the switch positions is a decimal system and the wheel is movable to any one of ten positions angularly spaced apart by approximately 36*.
 8. A multiple selector switch as defined in claim 5 wherein: the stationary contact means on said stationary switching member comprising a plurality of radially-spaced apart arcuate switch means, and the rotary contact means on said wheel comprises a plurality of rotary contacts similarly spaced apart radially for contacting said arcuate switch means in various combinations as said wheel is rotated; said rotary contacts being electrically connected together and to a common terminal throughout the wheel rotation; and the rotary contacts being arranged to connect said common terminal to a different combination of four terminals in each of its positions to represent a unit''s digit, a two''s digit, a four''s digit and an eight''s digit in accordance with the binary system.
 9. A switch as defined in claim 8 wherein each said compartment is substantially closed except for said open window in the front wall structure. 